中文摘要：

兼顾经济利益和能源供应安全是天然气进口国的重要考量。运用微分对策理论，构建了受出口国偏好和进口多元化程度影响的天然气进口国博弈模型，并获得了模型的最优解。研究表明，天然气进口国从某一个出口国的最优进口量与进口国愿意支付的最高价格和出口国的绝对偏好程度正相关。当天然气进口国的进口多元化程度高时，其达到初始预期进口需求总量的时间变短，有利于保障能源供应安全。但是天然气进口国的消费者剩余与本国进口多元化程度负相关，与其他竞争进口国的进口多元化程度正相关，且出口国相对偏好越低，该变化的幅度越大。因此，从获得经济利益的角度看，进口多元化程度并不是越高越好，研究发现，存在一个兼顾经济利益和能源供应安全的“进口多元化程度”。

英文摘要：

Gas importer should consider the trade-off between economic benefits and energy security. We explore a gas importer game model considering the exporter preference and diversification of energy, and obtain the explicit equilibrium. We demonstrate that importer＇s optimum imports have positive correlation with the highest price that the importer is willing to pay and the degree of absolute preference of exporter. When the Imports Diversification Degree （IDD） of importer is improved, the time reaching the initial expectations import demand is shorter and the security of energy supply is guaranteed. Importer＇ s consumer surplus has negative correlation with the domestic IDD, but has positive correlation with other countries＇ IDD. Furthermore, when the relative preference of exporter is lower, the amplitude of the change becomes larger. Therefore, from the perspective of economic interests, there exists an optimal ＂imports diversification＂ to balance the economic interest and energy security.